Lens assembly for indicator lights

ABSTRACT

The lamp holder includes a collar which is captured in a groove provided in the reflector section of a lamp housing by a cupshaped lens overlying and bonded, preferably ultrasonically, to the reflector section. Spring fingers extending from the collar of the lamp holder fit into slots provided in a barrel section of the lamp housing. The spring fingers have multiple bends forming two knee-like portions, one adapted to hold an indicator lamp and the other extending through slots provided in the barrel section, when an indicator lamp is installed. The latter knee-like portion engages the inside surface of the casing into which the lens assembly is installed and establishes electrical contact between the lamp and the casing.

United States Patent McNeil 1 51 July 18,1972

[54] LENS ASSEMBLY FOR INDICATOR LIGHTS [21] Appl. No.: 126,505

[52] US. Cl. ..240/l5l, 248/27, 339/176 L Primary Examiner-Samuel S. Matthews Assistant Examiner-Fred L. Braun Anomey-John W. Michael, Gerrit D. Foster, Bayard H. Michael, Paul R. Puerner, Joseph A. Gemignani, Robert E. Clemency, Andrew 0. Riteris, Glenn A. Buse and Spencer B. Michael ABSTRACT The lamp holder includes a collar which is captured in a groove provided in the reflector section of a lamp housing by a cup-shaped lens overlying and bonded, preferably ultrasonically, to the reflector section. Spring fingers extending from the collar of the lamp holder fit into slots provided in a barrel section of the lamp housing. The spring fingers have multiple bends forming two knee-like portions, one adapted to hold an indicator lamp and the other extending through slots provided in the barrel section, when an indicator lamp is installed. The latter knee-like portion engages the inside surface of the easing into which the lens assembly is installed and establishes electrical contact between the lamp and the casing.

4 Claim, 2 Drawing Figures LENS ASSEMBLY FOR INDICATOR LIGHTS BACKGROUND OF THE INVENTION Indicator light assemblies are used extensively for a variety of purposes in electrical equipment. For instance, they are commonly used on push button switches to indicate off or on positions and in electrical circuits to indicate which ones are closed. One type of lens assembly used in conjunction with the indicator light includes a housing carrying a lamp holder with a transparent or translucent lens covering the outer end of the housing. The housing fits into a casing which is mounted to the back side of a panel or similar mounting means. The casing includes terminals for connection to an electrical circuit, one terminal being electrically connected to the casing wall and another electrically connected to a contact engaged by the indicator lamp. The lamp holder serves the dual function of retaining the indicator lamp and establishing electrical contact between the lamp socket and the inside wall of the casing. For relamping, the lens assembly is removed from the front of the panel by pulling it out of the casing and the burned out lamp is removed from the rear of the lens assembly.

Generally, the lamp holders employed by prior art lens assemblies are in the form of a slotted metallic tube arranged with two or more spring fingers holding the lamp and two or more spring fingers engaging the inside wall of the casing. Because of the cost of the material used and the fabrication and assembling procedures required, the overall cost of lens assemblies employing this type of lamp holder is quite high.

SUMMARY OF THE INVENTION The simple arrangement of the lens lamp holder and lamp housing of the lens assembly of this invention described in the abstract permits the use of inexpensive materials and assembly by rapid, simplified techniques.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded, perspective view, partially sectioned, showing the components of the lens assembly.

FIG. 2 is a cross-section, elevation view showing the lens assembly of FIG. 1 assembled with a lamp installed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Lens assembly includes a transparent or translucent lens 12, lamp housing 14 and lamp holder 16 which holds a conventional flanged, flat base indicator lamp l8.

Lamp housing 14 has a tubular barrel section 20 which fits inside a conventional casing (not shown) mounted to back of a panel (not shown) or similar mounting means. The casing is of conventional design having one terminal electrically connected to its wall and another terminal connected to a contact adapted to be engaged by lamp base contact 22. Shoulder 24 on barrel section 20 slides inside the casing when lens assembly 10 is used with a push button switch. In other applications where the lens assembly is not depressed for operation, shoulder 24 is dimensioned to provide a pressure fit with the casing.

Cup-shaped lens 12 fits over and is bonded to reflector section 26 of the lamp housing 14. Lens 12 can have any convenient cross-section, such as rectangular (as shown in FIG. 1), square, circular, hexagonal, etc. with reflector section 26 of the lamp housing having a complementary shape.

Lamp holder 16, constructed from a resilient material, has a collar 30 with a plurality of legs 32, which act as spring fingers, extending therefrom. Collar 30 of lamp holder 16 is captured in groove 34 provided in reflector section 26 by lens 12 to prevent shifting. The axial length of collar equals the depth of groove 34 and lens 12 overlies at least a portion of the collar so that the lamp holder is locked in place. Legs 32 fit into complementary slots 36 provided in barrel section 20. Legs 32 are provided with multiple bends so that, when lamp I8 is installed as shown in FIG. 2, lamp base 38 engages and is held between first knee-like portions 40. Legs 32 are spread apart by the lamp base and the outer ends extend through slots 36, as shown in FIG. 2, so that second knee-like portions 42 can engage the inside wall of a casing when the lens assembly is installed therein. This establishes an electrical contact between the lamp base and the casing.

Lens 12 and lamp housing 14 are preferably molded from a thermoplastic material, such as various types of suitable butyrates, polyolefinic polymers and the like, so that they can be bonded together by conventional thermoplastic welding techniques, such as heat sealing or ultrasonic welding. Preferably, the top surface of reflector section 26 is provided with small projections 46 (as shown in FIG. 1) and lens 12 and lamp housing 14 are bonded together ultrasonically. Projections 46 act as energy directors during the welding operation and minimize the acoustical energy required to melt the material of the adjoining surfaces sufficiently to produce a good bond.

Lens assembly 10 is assembled by inserting lamp holder collar 30 into groove 34 and legs 32 into. slots 36 and then placing lens 12 over reflector section 26 with shoulder 48 engaging projections 46. As shown in FIG. 1, the collar and legs and the lamp holder are normally slightly sprung apart, i.e., must be compressed slightly for installation into groove 34 and slots 36. This insures that the lamp holder is maintained in a snug fit with the lamp housing during assembly. With the assembled unit positioned in an appropriately shaped fixture, an acoustic born (not shown), having a central aperture larger than the outside diameter of shoulder 24, is brought into compressive engagement with flange 50 on lamp housing 14. Acoustic energy is transmitted by the horn to lamp housing flange 50, through projections 46 to lens shoulder 48 and the adjoining surfaces are softened. The lamp housing and lens are maintained in compression, and upon cooling, an effective bond is produced therebetween at 52.

From the above description, it can be seen that the simple arrangement of the lens, lamp housing and lamp holder permit the use of inexpensive materials and rapid, inexpensive assembly techniques. Hence, the overall cost of the lens assembly of this invention is approximately one-tenth of that of prior art devices employing a slotted metallic sleeve as the lamp holder. Also, the arrangement provides a simple and reliable means for holding the lamp holder solidly in place thereby preventing shifting during lamp replacement and/or lens assembly installation into a casing.

lclaim:

I. An indicator light lens assembly comprising, in combination a lamp housing having a tubular barrel section and a centrally apertured reflector section integral with one end of said barrel section, said barrel section having a plurality or radially spaced elongated slots in the end opposite to the reflector section and said reflector section having a groove encircling said aperture;

an electrical indicator lamp having a base positioned inside said barrel section and a bulb portion extending through said aperture;

an electrically conductive lamp holder having a collar positioned in said groove and a plurality of radially spaced, spring fingers extending from said collar and disposed inside said barrel section, each of the fingers having multiple bends forming first and second knee-like portions with the first knee-like portion being engaged by and holding the base of said lamp and the second knee-like portion extending through the slots in said barrel section; and cup-shaped lens encompassing said bulb portion and mounted to said reflector section to capture said collar in said groove, said lamp being removable from said lamp housing through the end opposite said reflector section.

2. The lens assembly according to claim 1 wherein said lens and lamp housing are made from a thermoplastic material.

3. The lens assembly according to claim 2 wherein said lens and lamp housing are bonded together ultrasonically.

4. The lens assembly according to claim 3 wherein said reflector section is provided with projections on the top surface thereof which engage the underside of said lens during assembly.

232g? UNITED STATES PATENT OFFICE CERTIFICATE OF COEC'H Patent No. 3 678 ,261 Dated July '18 14972 lnv n fl Daniel E. McNeil It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Change the As signee from "Controls Switch, Inc." to

-- Control Switch, Inc.

Column 2, Claim 1, line 6 at the start of the line, change rill or to of Signed and sealed this 3rd day of April 1973 (SEAL) Attest: v

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

1. An indicator light lens assembly comprising, in combination a lamp housing having a tubular barrel sEction and a centrally apertured reflector section integral with one end of said barrel section, said barrel section having a plurality or radially spaced elongated slots in the end opposite to the reflector section and said reflector section having a groove encircling said aperture; an electrical indicator lamp having a base positioned inside said barrel section and a bulb portion extending through said aperture; an electrically conductive lamp holder having a collar positioned in said groove and a plurality of radially spaced, spring fingers extending from said collar and disposed inside said barrel section, each of the fingers having multiple bends forming first and second knee-like portions with the first knee-like portion being engaged by and holding the base of said lamp and the second knee-like portion extending through the slots in said barrel section; and a cup-shaped lens encompassing said bulb portion and mounted to said reflector section to capture said collar in said groove, said lamp being removable from said lamp housing through the end opposite said reflector section.
 2. The lens assembly according to claim 1 wherein said lens and lamp housing are made from a thermoplastic material.
 3. The lens assembly according to claim 2 wherein said lens and lamp housing are bonded together ultrasonically.
 4. The lens assembly according to claim 3 wherein said reflector section is provided with projections on the top surface thereof which engage the underside of said lens during assembly. 